Sibet Attena, a nephew and aid to Ulrich received the lordships Esens, Stedesdorf and Wittmund, which together formed the Harlingerland.
Firstly, he married Countess Walburgis of Rietberg (1556–1586), daughter and heiress of Count John II of Rietberg, Lord of Esens, Stedesdorf and Wittmund and Countess Agnes of Bentheim-Steinfurt.
From his first wife, Onna of Stedesdorf, a daughter of Hero Omken the Elder, he inherited Stedesdorf in 1447.
Sibet Attena, a nephew and ally of Ulrich, received the lordships Esens, Stedesdorf and Wittmund, which together formed the Harlingerland.